Socket system including a vacuum liner for prosthetic or orthotic devices and associated methods

ABSTRACT

The socket system includes a socket and a vacuum liner. A one-way valve is positioned within the closed distal end of the socket and provides controlled fluid communication between the interior socket space and an external environment. The closed distal end of the vacuum liner includes a distal portion formed of a higher durometer elastomeric material than the surrounding portions of the liner, and including a concave section extending from an external surface thereof towards the interior liner space. The socket, on the interior of the closed distal end thereof, includes a receiving portion that corresponds to and receives the distal portion of the vacuum liner (e.g. matching the perimeter and depth of the distal portion). The receiving portion includes a bottom surface (e.g. a flat surface) opposite to the concave section of the vacuum liner when received therein, and defining an exterior liner space therewith.

RELATED APPLICATION

This application claims priority to U.S. Ser. No. 13/317,279, filed Oct.13, 2011, which claims priority to a provisional application Ser. No.61/455,179 filed Oct. 15, 2010, the entire disclosure of which isincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to the field of prosthetic and orthoticliners (i.e. skin-socket interface liners), and more particularly tocustom and production (“off the shelf”) prosthetic liners, socketsystems and associated methods.

BACKGROUND OF THE INVENTION

Liners provide a soft, flexible interface between a residual limb of anamputee and a hard socket to which a prosthetic device is secured. Suchliners are typically made of an elastomeric material such as silicone.Such liners may also be used in connection with orthotic devices.Prosthetic suspension liners are described in prior patents, and may befabricated of elastomeric or rubber materials, and are used to cushion apost-operative stump or residual limb with respect to a prosthesis thatis installed over the residual limb and coupled to the liner, e.g. by aconventional locking device.

Such liners should conform closely with the residual limb, accommodateall surface contours and sub-surface bone elements of the residual limb,and provide a comfortable cushion between the residual limb and the hardsocket of the prosthesis that is to be fitted over the residual limb.Various silicone rubber or elastomeric materials are used for suspensionliners. Such elastomeric materials having an appropriatehardness/softness, elongation, tensile, and other properties, such asbio-inertness (resulting in no skin reaction), have been successfullyused for suspension liners.

The elastomeric forming the liner frictionally engages and remainsattached to the skin of a residual limb so that the limb is retainedwithin the prosthetic socket in a comfortable, non-irritating manner.For example, liners may be used for any level of amputation both upperand lower limb. Prosthetic liners are used to cushion the amputee'sresidual limb from shock during ambulation.

With the advent of vacuum assisted or suction socket systems theresidual limb is surrounded in a non-permeable material, and the socketis secured to the limb/liner via a vacuum link. A consequence of reducedor loss of vacuum is the possibility of losing the link between theliner and socket. A loss of linkage could result in the detachment orloss of the prosthesis.

Prior art approaches include applying external vacuum systems to theprosthesis to achieve enhanced suspension between the socket and theamputee. Such a prosthesis normally has four main suspension components.The socket is the rigid or semi-rigid structure that has a shapedesigned to encompass the residual limb. The liner is a softer interfacebetween the socket and the amputees residual limb. A seal contains thevacuum between the inner surface of the socket and the outer surface ofthe liner, and a vacuum pump or other means introduces vacuum into thespace between the inner surface of the socket and the outer surface ofthe liner.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a more reliablesocket system, liner and/or prosthetic device that enhances vacuum inthe space between the inner surface of the socket and the outer surfaceof the liner.

This and other objects, advantages and features in accordance with thepresent invention are provided by a socket system for use with aprosthetic device to be secured to a residual limb, and including asocket and a vacuum liner. The socket includes a cylindrical body havinga closed distal end and an open proximal end, and defining an interiorsocket space to receive the residual limb and donned vacuum liner. Atthe distal end of the socket, a one-way valve is positioned within theclosed distal end and provides controlled fluid communication betweenthe interior socket space and an external environment.

The vacuum liner includes an elongated elastomeric tube having a closeddistal end and an open proximal end, and defining an interior linerspace configured to receive the residual limb. The closed distal end ofthe vacuum liner includes a distal portion, formed of a higher durometerelastomer material than the surrounding portions of the liner, andincluding a concave section extending from an external surface thereoftowards the interior liner space. The distal portion may be aprotrusion, e.g. disk shaped, having an outer perimeter and depth.

The socket, on the interior of the closed distal end thereof, includes areceiving portion that corresponds to and receives the distal portion ofthe vacuum liner (e.g. matching the perimeter and depth of the distalportion). The receiving portion includes a bottom surface (e.g. a flatsurface) opposite to the concave section of the vacuum liner whenreceived therein, and defining an exterior liner space therewith.

When the amputee walks, such exterior liner space collapses under theweight of the amputee and forces the air that was contained therein outof the socket through the one-way valve (e.g. FIG. 3). As weight isrelieved from the prosthesis during swing phase, the higher durometerelastomer material of the distal portion is urged to return to itsoriginal shape, pulling air into the exterior liner space from thesurrounding socket (FIG. 4). This cycle is repeated as the amputee walksremoving air from the socket creating a vacuum.

The vacuum liner and higher durometer elastomer material of the distalportion can be manufactured in a two-stage pour with a correspondingmold, for example. The distal portion could also be adhered eitherpermanently by glue or temporally by hook and loop fastener, forexample. These are just examples and other methods of making may beavailable and considered.

Of course, the bottom surface of the receiving portion could be flat,concave or convex depending on the desired vacuum and/or comfort of theamputee. The concave section and corresponding bottom surface could bereversed (i.e. on the closed distal end of the vacuum liner and on theinterior of the closed distal end of the socket). Such configuration mayresult in a need to extend the length of the socket. The one-way valveis configured to allow the weight of a user, via the residual limb, toexpel air from the interior socket space out to the externalenvironment. The one-way valve may be a duckbill valve, for example,and/or have a cracking pressure of about 0.2 psi.

Objects, advantages and features in accordance with the presentinvention are also provided by a vacuum liner for use with a socket andassociated prosthetic device to be secured to a residual limb. Thesocket includes a cylindrical body having a closed distal end and anopen proximal end, and defining an interior socket space to receive theresidual limb and donned vacuum liner. At the distal end of the socket,a one-way valve is positioned within the closed distal end and providescontrolled fluid communication between the interior socket space and anexternal environment.

The vacuum liner includes an elongated elastomeric tube having a closeddistal end and an open proximal end, and defining an interior linerspace configured to receive the residual limb. The closed distal end ofthe vacuum liner includes a distal portion, formed of a higher durometerelastomer material than the surrounding portions of the liner, andincluding a concave section extending from an external surface thereoftowards the interior liner space. The distal portion may be aprotrusion, e.g. disk shaped, having an outer perimeter and depth.

The distal portion of the vacuum liner is configured to be received inthe socket, on the interior of the closed distal end thereof thatincludes a corresponding receiving portion (e.g. matching the perimeterand depth of the distal portion). The concave section of the vacuumliner is configured to define an exterior liner space when opposite abottom surface (e.g. a flat surface) of the receiving portion of thesocket.

Objects, advantages and features in accordance with the presentinvention are also provided by a method of making a socket system foruse with a prosthetic device to be secured to a residual limb, andincluding providing a socket and providing a vacuum liner. Providing thesocket includes forming a cylindrical body having a closed distal endand an open proximal end, and defining an interior socket space toreceive the residual limb and donned vacuum liner. At the distal end ofthe socket, a one-way valve is positioned within the closed distal endand provides controlled fluid communication between the interior socketspace and an external environment.

Providing the vacuum liner includes forming an elongated elastomerictube having a closed distal end and an open proximal end, and definingan interior liner space configured to receive the residual limb. Theclosed distal end of the vacuum liner includes a distal portion, formedof a higher durometer elastomer material than at least the surroundingportions of the liner, and including a concave section extending from anexternal surface thereof towards the interior liner space. The distalportion may be a protrusion, e.g. disk shaped, having an outer perimeterand depth.

The socket, on the interior of the closed distal end thereof, is formedto include a receiving portion that corresponds to and receives thedistal portion of the vacuum liner (e.g. matching the perimeter anddepth of the distal portion). The receiving portion includes a bottomsurface (e.g. a flat surface) opposite to the concave section of thevacuum liner when received therein, and defining an exterior liner spacetherewith.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of the vacuum liner in accordance withfeatures of an embodiment of the present invention.

FIG. 2 is a cross-sectional perspective view of the vacuum liner of FIG.1.

FIGS. 3 and 4 are cross-sectional views of a socket system including thevacuum liner of FIG. 1 in accordance with features of an embodiment ofthe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described more fully hereinafter withreference to the accompanying drawings in which preferred embodiments ofthe invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. Thedimensions of layers and regions may be exaggerated in the figures forease of explanation.

The following description refers to, by example, a liner associated witha lower limb (e.g. the knee), however, the features of the inventionapply to liners for use with any limb/joint area that may benefit fromthe use of vacuum assistance as described herein. Features of thepresent invention are directed to a prosthetic liner and associatedmethods of making and using, and includes the use of an elastomericmaterial, e.g. pourable or injectable silicone, that may be used with asimple mold or press. The silicone is preferably biocompatible, e.g.“healthcare grade” or “medical grade”, which is suitable for externaluse. For example, an appropriate silicone system may also be clear tosemi-translucent and curable at room temperature. The molded siliconeliner should have high tear strength and exhibit flexibility and highelasticity. Other elastomers or materials exhibiting the necessaryqualities of a skin-interface liner may also be used.

Referring to FIGS. 1-4, the approach of the present invention will bedescribed. It is an object of the present invention to provide a morereliable socket system 10, liner 20 and/or associated prosthetic devicethat enhances vacuum in the space between the inner surface of thesocket 12 and the outer surface of the liner 20.

This and other objects, advantages and features in accordance with thepresent invention are provided by a socket system 10 for use with aprosthetic device to be secured to a residual limb, and including asocket 12 and a vacuum liner 20. The socket 12 includes a cylindricalbody 14 having a closed distal end 15 and an open proximal end 16, anddefining an interior socket space 17 to receive the residual limb anddonned vacuum liner 20. At the distal end 15 of the socket 12, a one-wayvalve 40 is positioned within the closed distal end and providescontrolled fluid communication between the interior socket space 17 andan external environment.

A mounting plate 42 may also be included in the distal end 15, as wouldbe appreciated by those skilled in the art. A vacuum seal (not shown)may also be provided adjacent the proximal end 16 of the socket adjacentand/or on an interior or exterior surface thereof, as would also beappreciated by those skilled in the art.

The vacuum liner 20 includes an elongated elastomeric tube 22 having aclosed distal end 23 and an open proximal end 24, and defining aninterior liner space 25 configured to receive the residual limb. Theelastomeric tube 22 of the liner 20 is formed of an elastomeric materialhaving an appropriate durometer. The liner 20 is donned by an amputeewith the closed end 23 adjacent and preferably in close contact with adistal end of the residual limb. The closed distal end 23 of the vacuumliner 20 includes a distal portion 26, formed of a higher durometerelastomeric material than the surrounding portions of the liner 20, andincluding a concave section 27 extending from an external surfacethereof towards the interior liner space 25. The distal portion 26 maybe a protrusion, e.g. disk shaped, having an outer perimeter and depth.

For example, the durometer hardness of the elastomeric tube 22 may bebetween 38-55 while the durometer hardness of the distal portion 26 maybe between 60-90 on the Shore-OO scale. The durometer hardness of therelative areas may vary depending upon patient weight and potentialactivity level.

The socket 12, on the interior of the closed distal end 15 thereof,includes a receiving portion 18 that corresponds to and receives thedistal portion 26 of the vacuum liner 20 (e.g. matching the perimeterand depth of the distal portion). The receiving portion 18 includes abottom surface 19 (e.g. a flat surface) opposite to the concave section27 of the vacuum liner 20 when received therein, and defining anexterior liner space 28 therewith.

When the amputee walks, such exterior liner space 28 collapses under theweight of the amputee and forces the air that was contained therein outof the socket 12 through the one-way valve 40 (e.g. FIG. 3). As weightis relieved from the prosthesis during the swing phase, the higherdurometer elastomeric material of the distal portion 26 is urged toreturn to its original shape, pulling air into the exterior liner space28 from the surrounding socket (FIG. 4). This cycle is repeated as theamputee walks removing air from the socket creating a vacuum. Thus, thedistal portion 26 and concave section 27 of the vacuum liner 20 incombination with the receiving portion 18 and bottom surface 19 of thesocket 12, define a vacuum pump.

The vacuum liner 20 and higher durometer elastomeric material of thedistal portion 26 can be manufactured in a two-stage pour with acorresponding mold, for example. In other words, the elastomeric tube 22and distal portion 26 are preferably integrally formed as a monolithicunit. The distal portion 26 could also be adhered either permanently byglue or temporally by hook and loop fastener, for example. These arejust examples and other methods of making may be available andconsidered.

Of course, the bottom surface 19 of the receiving portion 18 could beflat, concave or convex depending on the desired vacuum and/or comfortof the amputee. The concave section 27 and corresponding bottom surface19 could be reversed (i.e. on the closed distal end 23 of the vacuumliner 20 and on the interior of the closed distal end 15 of the socket12). Such configuration may result in a need to extend the length of thesocket. The one-way valve 40 is configured to allow the weight of auser, via the residual limb, to expel air from the interior socketspace, i.e. from the interface between the outer surface of the liner 20and the inner surface of the socket 12, out to the external environment.

A type of one-way valve 20 is a duckbill valve which is made of rubberand has a low cracking pressure, about 0.2 psi. Other types of one-wayvalves are also available and may be used in the present approach. Theone-way valve 40 should not allow air, moisture or any other contaminateto enter the interior space 17 of the socket 12.

Objects, advantages and features in accordance with the presentinvention are also provided by a vacuum liner 20 for use with a socket12 and associated prosthetic device to be secured to a residual limb.

The vacuum liner 20 includes an elongated elastomeric tube 22 having aclosed distal end 23 and an open proximal end 24, and defining aninterior liner space 25 configured to receive the residual limb. Theclosed distal end 23 of the vacuum liner includes a distal portion 26,formed of a higher durometer elastomeric material than the surroundingportions of the liner 20, and including a concave section 27 extendingfrom an external surface thereof towards the interior liner space 25.The distal portion 26 may be a protrusion, e.g. disk shaped, having anouter perimeter and depth.

The distal portion 26 of the vacuum liner 20 is configured to bereceived in the socket 12 on the interior of the closed distal end 15thereof that includes a corresponding receiving portion 18 (e.g.matching the perimeter and depth of the distal portion). The concavesection 27 of the vacuum liner 20 is configured to define an exteriorliner space 28 when opposite a bottom surface 19 (e.g. a flat surface)of the receiving portion 18 of the socket 12.

Objects, advantages and features in accordance with the presentinvention are also provided by a method of making a socket system 10 foruse with a prosthetic device to be secured to a residual limb, andincluding providing a socket 12 and providing a vacuum liner 20.Providing the socket 12 includes forming a cylindrical body 14 having aclosed distal end 15 and an open proximal end 16, and defining aninterior socket space 17 to receive the residual limb and donned vacuumliner 20. At the distal end 15 of the socket 12, a one-way valve 40 ispositioned within the closed distal end and provides controlled fluidcommunication between the interior socket space 17 and an externalenvironment.

Providing the vacuum liner 20 includes forming an elongated elastomerictube 22 having a closed distal end 23 and an open proximal end 24, anddefining an interior liner space 25 configured to receive the residuallimb. The closed distal end 23 of the vacuum liner 20 includes a distalportion 26 formed of a higher durometer elastomeric material than atleast the surrounding portions of the liner 20, and including a concavesection 27 extending from an external surface thereof towards theinterior liner space. The distal portion 26 may be a protrusion, e.g.disk shaped, having an outer perimeter and depth.

The socket 12, on the interior of the closed distal end 15 thereof, isformed to include a receiving portion 18 that corresponds to andreceives the distal portion 26 of the vacuum liner 20 (e.g. matching theperimeter and depth of the distal portion). The receiving portion 18includes a bottom surface 19 (e.g. a flat surface) opposite to theconcave section 27 of the vacuum liner 20 when received therein, anddefining an exterior liner space 28 therewith.

Thus, the weight of the amputee during ambulation will create enoughforce to push or expel air out of the interior socket space through theone-way valve 40 keeping the residual limb secured to the socket 12 viaan associated vacuum link.

Many modifications and other embodiments of the invention will come tothe mind of one skilled in the art having the benefit of the teachingspresented in the foregoing descriptions and the associated drawings.Therefore, it is to be understood that the invention is not to belimited to the specific embodiments disclosed, and that modificationsand embodiments are intended to be included within the scope of theappended claims.

That which is claimed is:
 1. A vacuum liner for use with a prostheticdevice for an amputee, the prosthetic device including a socket having avalve, the vacuum liner arranged to be secured to a residual limb, thevacuum liner comprising: an elongated tube defining a central axis, andhaving a closed distal end and an open proximal end located along thecentral axis, and the elongated tube defining an interior liner spaceconfigured to receive the residual limb; a distal portion forming aprotrusion located at a bottom of the distal end of the elongated tubeand defining an exterior liner space including a recessed surfacelocated a depth into the protrusion and extending towards the distal endof the elongated tube, the protrusion being coaxial with the centralaxis; wherein the distal portion is sized and configured for matingagainst the socket so that when an amputee walks, the exterior linerspace collapses under weight of the amputee and forces air containedtherein out of the socket through the valve, and as weight is relievedfrom the prosthetic device during a swing phase of walking, theprotrusion is urged to return to a predetermined, non-collapsed shape,pulling air into the exterior liner space from the socket.
 2. The vacuumliner of claim 1, wherein the protrusion is disk-shaped.
 3. The vacuumliner of claim 1, wherein the distal portion is formed of a higherdurometer material than surrounding portions of the elongated tube. 4.The vacuum liner of claim 3, wherein a durometer hardness of theelongated tube is between 38-55 on the Shore-OO scale, while a durometerhardness of the distal portion is between 60-90 on the Shore-OO scale.5. The vacuum liner of claim 1, wherein the recessed surface is concaveand is integrally formed with the elongated tube as a monolithic unit.6. The vacuum liner of claim 1, wherein the distal end integrally formsthe distal portion.
 7. The vacuum liner of claim 1, wherein a bottomperiphery of the distal portion is flat.
 8. The vacuum liner of claim 1,wherein the distal end of the liner has a thickness that is thicker thana thickness at the open proximal end.
 9. The vacuum liner of claim 1,wherein the liner is formed from an elastomeric material.